This guy is amazing. I can't even upload videos in the public domain (old movies) without getting an auto-takedown from YouTube's content algorithm...somehow he manages to post a video that includes one of the most famous tracks in rap history?
(slightly less non-facetious question: maybe NWA has asked YouTube to whitelist their work?)
More relevant comment, as if it were going to be a big surprise: the attack vector was SQL injection into what appears to be a custom built PHP site: https://youtu.be/QoSrjrYC3hI?t=6m16s